Saying it was a deal they could not accept, the NBA players union voted Monday to disband rather than agree to the league’s latest proposal that could have ended the 137-day lockout.

Seth Wenig / The Associated Press

It puts the entire 2011-12 season in jeopardy, with the players preparing to file an antitrust lawsuit within the next two days against the league for damages caused from the lockout, said Billy Hunter, the executive director of the now-defunct National Basketball Players Association.

“I think they have made a bunch of bad decisions, and this is just one of them,” said Marc Ganis, a Chicago-based sports consultant, referring to the player union’s decision to disband. “This changes the equation because if they do file the antitrust suit, it changes the timeline, changes the equation and puts it in the hands of the lawyers rather than in the hands of union officials.’’

By disbanding and filing an antitrust suit, all existing player contracts will become void.

If the entire season is lost, it means Hornets star Chris Paul already might have played his final game with the franchise because he can opt out of his contract at the end of the 2011-12 season. But there could be a scenario like what occurred in the National Hockey League when it lost the entire 2004-05 season because of labor problems, where existing contracts remained as they were before the season was lost. Paul has not indicated whether he would sign an extension to remain with the Hornets.

With the prospect of a lengthy court battle ahead to solve the league’s labor mess, it’s a blow to the Hornets, who were enjoying one of their best sales campaigns in franchise history.

The Hornets are 440 season tickets away from meeting their objective of 10,000. Teams officials declined to comment Monday but said they have a refund policy in place for fans.

Hunter announced the union’s decision after meeting with players, which included player representatives from all 30 teams, for more than four hours Monday. Paul, the Hornets’ player representative, and center Emeka Okafor were among the players attending Monday’s meeting in New York.

Instead of continuing labor negotiations, the union will file a lawsuit seeking judgment against the NBA for damages caused by the lockout, where players are expected to lose up to $350 million in salaries because of the cancelation of the entire November schedule. The league also has lost millions of dollars because of the lost games. Had the season been going on as scheduled, players were due to receive their first paychecks today, according to a league source.

“The players have decided under the circumstances they are taking the appropriate action,” Hunter said. “In some instances in the (latest) proposal made by the NBA was regressive as opposed to becoming more open and flexible for the players. It was a system that we felt we couldn’t function. For the most part, we had a hard cap, extreme tax and a reduction in length of contracts.”

Said New Orleans Mayor Mitch Landrieu: “I don’t think it’s a good idea to decertify the union. I don’t think that’s going to work out well. It’s certainly bad for the city the longer they continue. Specifically because of the precarious position that we’re in right now with the Hornets. So I was disheartened by that.”

NBA Commissioner David Stern issued an ultimatum last week to the players union that if it didn’t accept the latest offer of a 50 percent share of the basketball-related income, the next offer would be substantially worse and would include only a 47 percent share and a hard-salary cap. Stern said if the latest proposal would have been accepted by the players, they would have played a 72-game schedule starting Dec. 15.

The league has sought a system where small-market teams can compete more equally with bigger-market teams. The league also wanted a bigger share of the nearly $4 billion in revenue. It announced earlier this year that 22 of the league’s 30 teams were losing money. Under the previous labor agreement, the players took in a 57 percent share of the basketball-related income.

In a statement, Stern said union attorney Jeffrey Kessler threatened during a bargaining session last year that the players would abandon the collective bargaining process and start an antitrust lawsuit if they did not get a bargaining resolution that they found acceptable.

“In anticipation of this day, the NBA filed an unfair labor practice charge before the National Labor Relations Board asserting that by virtue of its continued threats, the union was not bargaining in good faith,” Stern said. “We also began a litigation in federal court in anticipating of this same bargaining tactic.

“The NBA has negotiated in good faith throughout the collective bargaining process, but because our revised bargaining proposal was not to its liking, the union decided to make good on Mr. Kessler’s threat.”